External pacemakers can be used for the transcutaneous stimulation of the heart. Likewise, it is possible to perform intracardiac stimulation using an external pacemaker and an electrode which is introduced into the heart through a vein. In both instances, however, the external pacemaker generally constitutes only a temporary solution because the treatment is associated with undesirable side effects, such as an undesirable stimulation of other muscle tissue located in the vicinity of the heart, for example, the rib muscles, or an increased risk of infection. On the other hand, compared to implantable pacemakers, external pacemakers offer the obvious advantage that a replacement of parts or of the entire pacemaker is possible without difficulty.
In particular, the battery used for operating the external pacemaker can be replaced, while, in the case of an implanted pacemaker, this is possible only within the context of surgery and replacement of the entire device. External pacemakers are subject to standard specifications, which are intended to ensure fast replacement of the battery and reliable operation of the pacemaker at the same time. In particular, one of the concerns is to provide a mechanism which is easy to operate and secured to prevent inadvertent opening, such as when being dropped. This is important, because the hospital staff must also replace the battery under time constraints and without specific training. In addition, it is to be ensured that the battery cannot be touched until the battery poles have a certain distance from the contacts of the pacemaker.
From U.S. Pat. No. 5,637,417, an external pacemaker comprising a battery drawer is known, which allows a replaceable battery to be received. The battery drawer is opened by pushing a button on the outside of the pacemaker housing, thereby actuating a release mechanism. This has the disadvantage that the battery drawer may open if the external pacemaker is dropped. In addition, the mechanism is not self-explanatory because the button for opening the drawer is provided in a different location of the pacemaker than the location at which the battery drawer opens. In addition, due to the release mechanism, the battery can inadvertently fall out of the battery drawer, as it is not apparent while pressing the button which way the pacemaker must be held, so that the removal side of the battery drawer may be pointed downward at the time it is released. Another disadvantage of the pacemaker disclosed in U.S. Pat. No. 5,637,417 is the contacting of the battery, which is implemented by spring contacts. The present invention is directed toward overcoming one or more of the above-identified problems.